The present invention relates to a vehicle wiper device.
Japanese Laid-Open Patent Publication No. 4-197854 describes a vehicle wiper device including drive devices located below a windshield at two ends in the widthwise direction of the vehicle. Each drive device includes a drive source (motor body and speed reduction unit) and a link mechanism. Each link mechanism includes a wiper coupling shaft coupled to a wiper. In the vehicle wiper device, the link mechanism also reduces the speed and increases the torque. This allows for reduction in the torque generated by the drive source, which is used to swing the wiper with a predetermined torque, and allows for miniaturization of the drive source.
In such a vehicle wiper device, a wiper fixing shaft is located at a certain position relative to the vehicle body, and the wiper produces a simple rotational action about the axis of the wiper fixing shaft. Thus, the wiper has a wiping range of the wiper having a simple sectoral shape. In recent vehicle wiper devices, a stop position (retraction stop position or the like at the rear side of the hood) is set below a lower reversing position for wiping operations to improve the range of view and improve the appearance as viewed from outside the passenger compartment.
In the vehicle wiper device described above, for example, it is preferable that the wiper be substantially horizontal at the stop position so that the wiper can be completely retracted and the appearance can be improved. When the wiper device is set in such a manner, the wiper is not horizontal at the lower reversing position and is inclined. This makes it difficult to obtain the desired wiping range. Obviously, when the wiper is set to be substantially horizontal at the lower reversing position instead, the wiper is not horizontal at the stop position. This makes it difficult to retract the wiper and adversely affects the appearance.
Further, the moving speed (velocity) of the wiper is low at the basal end of the wiper but high at the distal end. Thus, the stop position of the distal end tends to easily vary. As a result, interference may occur, for example, between the wipers or between the wiper and the vehicle body due to variations in the stop position of the distal end of the wiper. To avoid such a situation, in the prior art, the stop position of the wiper is set in advance so that the wipers are separated to each other by relatively distance at the stop position. Alternatively, the stop position is set in advance so that the wiper stops at a position separated from the vehicle body. Thus, the appearance is poor when the wipers are stopped.